Electron tube and optical splitter

Abstract

The invention relates to an electron tube and an optical splitter. This electron tube is used by being attached to an external device, and is provided with: a housing that has a light incidence window that includes a light incidence surface and that causes light from the external device to enter through the light incidence surface; and a photoelectric conversion unit that is disposed in the housing so as to face the light incident window, and that emits electrons in accordance with the light incident from the light incident window. And an electron multiplication unit which is disposed in the housing and multiplies the electrons emitted from the photoelectric conversion unit. And a positioning member which is formed separately from the light incident window, is fixed to the light incident surface, and has a light passage part through which the light from the external device passes toward the light incident surface, the positioning member having a reference part which serves as a reference for mechanical positioning with respect to the external device.

Description

Technical Field

[0001] The present invention relates to an electron tube and a spectroscope. Background Art

[0002] Japanese Patent Publication No. 6508140 discloses a photomultiplier tube having a main body and a support provided at an end of the main body. The main body includes: a cylindrical member having light transmissivity; and a photomultiplier section accommodated in the cylindrical member and having a cathode and a multiplier electrode. The cathode receives light incident from the outside of the cylindrical member and emits photoelectrons. The emitted photoelectrons are incident on the multiplier electrode.

[0003] The photomultiplier tube is installed in a measuring device having a light emitting section that causes an analysis sample to emit light. Specifically, the photomultiplier tube is fixed by inserting bolts through a fixing hole of the support and a through hole of a relative member of the measuring device provided at a position corresponding to the fixing hole. Summary of the Invention

[0004] However, generally, due to manufacturing-related influences such as tolerances of constituent parts, assembly accuracy, and heating processes during manufacturing, it is sometimes difficult for a photomultiplier tube to achieve the same mechanical accuracy as designed. Therefore, individual differences may occur. For example, even when installed in an external device such as the above-described measuring device in the same manner, differences in the optical positional relationship may occur. Therefore, even for the same input signal, differences in the output signals shown by the external device may occur. In such a case, fine adjustment of the installation state to the external device is required, and it becomes an adjustment operation for simultaneously operating the external device, which is not easy.

[0005] Therefore, an object of one aspect of the present invention is to provide an electron tube and a spectroscope that can be easily and highly accurately positioned.

[0006] An electron tube according to one aspect of the present invention is [1] "an electron tube that is used by being installed in an external device and includes: a frame having a light incident window including a light incident surface and allowing light from the external device to enter through the light incident surface; a photoelectric conversion section disposed in the frame opposite to the light incident window and emitting electrons according to the light incident through the light incident window; an electron multiplication section disposed in the frame and multiplying the electrons emitted from the photoelectric conversion section; and a positioning member that is formed separately from the light incident window and fixed to the light incident surface, has a light passage portion that allows the light from the external device to pass through the light incident surface, and the positioning member has a reference portion that serves as a reference for mechanical positioning with respect to the external device".

[0007] The electron tube includes: a housing including a light incident window; a photoelectric conversion section and an electron multiplication section disposed inside the housing; and a positioning member fixed to the light incident surface of the light incident window. Then, the positioning member has a reference portion that serves as a reference for mechanical positioning with respect to an external device. The positioning member is formed separately from the light incident window and fixed to the light incident window. Therefore, after the positioning member is completed as an electron tube (after the manufacturing process of the electron tube is completed), that is, after the change in mechanical accuracy caused by the influence related to the manufacturing of the electron tube is determined, the positioning member can be fixed to the light incident window in a desired state. Therefore, the reference portion of the positioning member is hardly affected by the manufacturing of the electron tube. Therefore, when the electron tube is mounted on an external device, by using the reference portion of the positioning member, high-precision positioning corresponding to the mechanical accuracy of the reference portion can be performed. Therefore, according to this electron tube, easy and high-precision positioning can be performed with respect to an external device.

[0008] The electron tube according to one aspect of the present invention may also be "[2] The electron tube according to [1] above, wherein the positioning member is fixed to the light incident surface in such a manner that the light passing portion faces the photoelectric conversion section and the light that has passed through the light passing portion is incident on a desired area of the photoelectric conversion section". In this case, high-precision positioning such as guiding light from an external device to an appropriate area of the photoelectric conversion section can be performed.

[0009] The electron tube according to one aspect of the present invention may also be "[3] The electron tube according to [1] or [2] above, wherein a marking portion is formed in at least one of the positioning member, the base material portion provided with the photoelectric conversion section, and the electron multiplication section". In this case, high-precision positioning can be performed through the marking portion.

[0010] The electron tube according to one aspect of the present invention may also be "[4] The electron tube according to any one of [1] to [3], wherein the electron multiplication section has a plurality of channels arranged in at least one direction for multiplying each of the electrons emitted from the photoelectric conversion section according to each of the plurality of lights incident from the light incident window". In this way, in the case where the electron multiplication section has a plurality of channels (in the case of a multi-channel), easy and high-precision positioning with respect to an external device can be more effectively achieved. For example, when a multi-channel electron tube is mounted on a spectrometer as an external device, it is necessary to position each channel of the electron tube at the arrival position of light of each wavelength split by the spectrometer. In this case, it is preferable that high-precision positioning of the electron tube with respect to the spectrometer can be easily performed.

[0011] The electron tube according to one aspect of the present invention may also be "[5] the electron tube according to any one of [1] to [4] above, wherein the positioning member has: an optical element disposed in the light passage portion, receiving the incidence of the light from the external device, and emitting the light to the light incident surface". In this case, if an optical element is added to the positioning member that undertakes the function of highly precisely positioning the external device, light guiding can be performed highly precisely by the highly precisely arranged optical element.

[0012] The electron tube according to one aspect of the present invention may also be "[6] the electron tube according to any one of [1] to [5] above, wherein the reference portion has a position reference that is a reference for the position relative to the external device and an angle reference that is a reference for the angle relative to the external device". In this case, the position and angle relative to the external device can be determined easily and highly precisely.

[0013] The electron tube according to one aspect of the present invention may also be "[7] the electron tube according to any one of [1] to [6] above, wherein the reference portion includes at least one of a protrusion, a hole, a notch, and an end face formed in the positioning member". In this case, the reference portion can be constituted by a simple mechanical structure.

[0014] The electron tube according to one aspect of the present invention may also be "[8] the electron tube according to any one of [1] to [7] above, wherein the positioning member has a first surface on the light incident surface side and a second surface on the side opposite to the first surface, and an antireflection film is formed on at least one of the first surface and the second surface". In this case, the reflection of light in the positioning member can be reduced.

[0015] The electron tube according to one aspect of the present invention may also be "[9] the electron tube according to any one of [1] to [4] above, wherein an opening for exposing the light incident surface to the outside is formed in the light passage portion". In this case, light from the external device can be incident on the light incident surface without reflection and refraction in the positioning member.

[0016] The electron tube according to one aspect of the present invention may also be "

[10] the electron tube according to [4] above, wherein the positioning member includes: an optical element disposed in the light passage portion, receiving the incidence of the light from the external device, and emitting the light to the light incident surface, and the optical element includes a plurality of optical structures aligned with respective positions of the plurality of channels". In this case, light can be efficiently incident on the plurality of channels of the electron multiplier portion respectively.

[0017] The electron tube according to one aspect of the present invention may also be "

[11] the electron tube according to

[10] above, which includes a condensing element provided on the surface of the optical element opposite to the light incident surface and having a condensing structure in a plane intersecting the arrangement direction of the channels". In this case, the field of view in the plane intersecting the arrangement direction of the plurality of channels can be expanded.

[0018] The spectroscope according to one aspect of the present invention is "

[12] a spectroscope that includes a spectroscopic unit of the external device for splitting the detection light into lights of a plurality of wavelengths and emitting them, and the electron tube according to any one of [1] to

[11] above". In this case, the electron tube can be easily and highly accurately positioned relative to the spectroscopic unit.

[0019] The spectroscope according to one aspect of the present invention may also be "

[13] the spectroscope according to

[12] above, which includes a dispersing element arranged on the optical path of the detection light for splitting the detection light into lights of the plurality of wavelengths, and a wavelength selection element arranged on the optical path of the detection light in front of the dispersing element for reflecting or absorbing light of a specific wavelength band of the detection light". In this case, the light that becomes noise with respect to the detection light can be reflected or absorbed by the wavelength selection element.

[0020] According to one aspect of the present invention, an electron tube and a spectroscope that can be easily and highly accurately positioned can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram showing the spectroscope according to the present embodiment.

[0022] Figure 2 It is a cross-sectional view of the electron tube and the housing accommodating the electron tube.

[0023] Figure 3 It is a top view of the housing accommodating the electron tube.

[0024] Figure 4 It is a perspective view of the electron tube.

[0025] Figure 5 It is a top view of the electron tube.

[0026] Figure 6 It is a schematic cross-sectional view of the electron tube.

[0027] Figure 7 It is a schematic top view of the electron multiplication unit.

[0028] Figure 8 (a) of it is a top view of the positioning member. Figure 8(b) is a top view of the electron multiplication section. Figure 8 (c) is a top view of a state in which a positioning member is arranged on the electron multiplication section.

[0029] Figure 9 is a diagram schematically showing a case where light emitted from a cylindrical lens array is incident on a plurality of channels of an electron multiplication section.

[0030] Figure 10 (a) and (b) are diagrams for explaining a method of aligning the position of a positioning member without using a reference line.

[0031] Figure 11 (a) and (b) are diagrams showing modified examples of the positioning member.

[0032] Figure 12 (a) and (b) are diagrams showing modified examples of the positioning member.

[0033] Figure 13 is a diagram showing a modified example of the positioning member.

[0034] Figure 14 is a diagram showing a modified example of the positioning member.

[0035] Figure 15 is a cross-sectional view of an electron tube and a housing accommodating the electron tube according to a modified example.

[0036] Figure 16 (a) is a schematic diagram showing an electron tube as a photomultiplier tube according to a modified example. Figure 16 (b) is Figure 16 a top view of the positioning member of (a). Figure 16 (c) is Figure 16 a top view of the electron multiplication section of (a).

[0037] Figure 17 is a schematic diagram showing an electron tube as a photomultiplier tube according to a modified example.

[0038] Figure 18 is Figure 17 a top view of the positioning member according to a modified example. Detailed implementation mode

[0039] Hereinafter, with reference to the drawings, an electron tube and a spectroscope according to one embodiment will be described. In addition, in the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and repeated descriptions may be omitted. Further, in each drawing, a rectangular coordinate system constituted by an axis defining a first direction D1, an axis defining a second direction D2 intersecting the first direction D1, and an axis defining a third direction intersecting the first direction D1 and the second direction D2 may be shown.

[0040] Figure 1 It is a schematic cross-sectional view of the optical splitter according to this embodiment. Figure 1 The optical splitter 1 shown can be used, for example, for spectroscopic measurement of weak light such as fluorescence or Raman scattered light, and in particular can be used for a flow cytometer.

[0041] Figure 1 The optical splitter 1 shown includes a spectroscopic unit (external device) 2 and a detection unit 3. The spectroscopic unit 2 splits the detection light L1 emitted from the optical fiber 4 into lights L2 of multiple wavelengths and emits them to the detection unit 3.

[0042] The spectroscopic unit 2 has a housing 10 and an optical system 20. The housing 10 has a receiving portion 11 and a mounting portion 12. The receiving portion 11 houses the optical system 20. The optical fiber 4 is mounted in the receiving portion 11, including one end portion where the detection light L1 guided by the optical fiber 4 is incident, and the other end portion where each of the split lights L2 is emitted. The mounting portion 12 is disposed at the other end portion. The mounting portion 12 has a surface 12a on the side opposite to the receiving portion 11. In order to accurately position the detection unit 3 relative to the spectroscopic unit 2, a plurality of positioning pins 12c for insertion into the through hole 212 described below are formed on the surface 12a.

[0043] The optical system 20 has a collimating lens 21, a filter (wavelength selection element) 22, a diffraction grating (dispersion element) 23, and an imaging lens 24. The detection light L1 emitted from the optical fiber 4 sequentially passes through the collimating lens 21 and the filter 22 and is incident on the diffraction grating 23. The collimating lens 21 collimates the detection light L1 emitted from the optical fiber 4 and emits it to the filter 22. In addition, in this embodiment, the collimating lens 21, the filter 22, the diffraction grating 23, and the imaging lens 24 of the optical system 20 are each composed of a single optical element, but they may also be each composed of a plurality of optical elements.

[0044] The filter 22 is disposed in front of the diffraction grating 23 on the optical path of the detection light L1. Specifically, the filter 22 is disposed between the collimating lens 21 and the diffraction grating 23 on the optical path of the detection light L1. The filter 22 selects the wavelength of the light toward the diffraction grating 23 by reflecting or absorbing light of a specific band included in the detection light L1 (for example, the excitation light of the measurement object of the spectroscopic unit 2). Thereby, it is possible to reflect or absorb the light that becomes noise with respect to the detection light L1 through the filter 22.

[0045] As an example, the diffraction grating 23 is a transmissive diffraction grating that splits the detection light L1 incident from the filter 22 into lights L2 of multiple bands and emits each of the lights L2 toward the imaging lens 24. The light L2 emitted from the diffraction grating 23 passes through the imaging lens 24 and is incident on the following light incident surface 102a of the electron tube 100. Additionally, the diffraction grating 23 can be a reflective diffraction grating, or a prism can be used instead of the diffraction grating. The imaging lens 24 images the light L2 emitted from the diffraction grating 23 on the following light incident surface 102a.

[0046] The detection unit 3 includes an electron tube 100 and a housing 200. The electron tube 100 is, for example, an HPD (hybrid photodetector). The electron tube 100 detects the light emitted from the spectroscopic unit 2. The electron tube 100 is mounted on the spectroscopic unit 2 so as to face the imaging lens 24. Specifically, in a state of being accommodated in the housing 200, the electron tube 100 is fixed to the mounting portion 12 of the spectroscopic unit 2 via the housing 200. Hereinafter, after first explaining the structure of the housing 200, the structure of the electron tube 100 will be described. Additionally, the direction in which the imaging lens 24 faces the following light incident surface 102a (i.e., the direction intersecting the light incident surface 102a) is defined as the first direction D1.

[0047] Refer to Figures 1 to 3 , and explain the structure of the housing 200. Figure 2 is a cross-sectional view of the detection unit 3. Figure 3 is a view of the detection unit 3 observed from the side of the imaging lens 24.

[0048] The housing 200 includes a top plate 201, a side wall portion 202, and a cover member 203. The housing 200 houses the electron tube 100.

[0049] The top plate 201 is formed in a plate shape. The top plate 201 has a first surface 201a and a second surface 201b on the side opposite to the first surface 201a. The first surface 201a faces the surface 12a of the mounting portion 12 in the first direction D1. The second surface 201b faces the light incident surface 102a of the electron tube 100 in the first direction D1. As an example, when observed from the first direction D1, the top plate 201 is formed in a rectangular shape with the four corners cut into semicircles.

[0050] The top plate 201 has an opening 211, a plurality of through holes 212, a protrusion 213, a pair of protrusion portions 214, and a recess 215.

[0051] When observed from the first direction D1, the opening 211 exposes the following positioning member 120 of the electron tube 100. Thus, the light L2 emitted from the spectroscopic unit 2 is incident on the positioning member 120 via the opening 211.

[0052] The plurality of through holes 212 are through holes formed in the top plate 201 along the first direction D1. The plurality of through holes 212 are mechanical references that define the positional relationship between the spectral splitting unit 2 and the housing 200 (detection unit 3). When observed from the first direction D1, the plurality of through holes 212 are formed at positions corresponding to the plurality of positioning pins 12c of the mounting portion 12. By inserting the positioning pins 12c into the through holes 212, the detection unit 3 is fixed to the mounting portion 12 via the top plate 201. The insertion structure of the positioning pins 12c and the through holes 212 can be formed such that the outer wall surface of the positioning pins 12c and the inner wall surface of the through holes 212 are separated by a gap of about several micrometers, so that very high-precision positioning can be performed. Then, the spectral splitting unit 2 and the housing 200 (detection unit 3) are positioned by the insertion structure of the positioning pins 12c and the through holes 212, and are reliably joined by a screwing structure formed by screws and threaded hole portions (not shown). Thus, the positional relationship between the spectral splitting unit 2 and the housing 200 (detection unit 3) is mechanically defined.

[0053] The protruding portion 213 is formed on the second surface 201b of the top plate 201. When observed from the first direction D1, the protruding portion 213 is formed inside the following side tube 103 of the electron tube 100. The protruding portion 213 is in contact with the light incident surface 102a of the electron tube 100. The protruding portion 213 is formed in a circular ring shape, for example, when observed from the first direction D1.

[0054] A pair of protruding portions 214 are formed on the second surface 201b of the top plate 201. The pair of protruding portions 214 are mechanical references for defining the positional relationship between the electron tube 100 and the housing 200. When observed from the first direction D1, the pair of protruding portions 214 are provided at positions closer to the inside than the protruding portion 213, and are formed to face each other in the second direction D2 with the opening portion 211 therebetween. The pair of protruding portions 214 extend cylindrically from the second surface 201b toward the light incident surface 102a, for example.

[0055] The concave portion 215 is formed on the first surface 201a of the top plate 201. The concave portion 215 is formed in a cylindrical shape. The concave portion 215 has an annular bottom surface 215a. The above-mentioned opening portion 211 is formed in this bottom surface 215a. A wavelength selection filter (not shown) arranged to cover the opening portion 211 is accommodated inside the concave portion 215 on the bottom surface 215a. This filter is used to remove, for example, the second-order diffracted light generated by the diffraction grating 23, and is configured to be arranged with a plurality of wavelength selection filters, for example, in such a way that unnecessary second-order diffracted light can be removed for each of the following channels ch.

[0056] The side wall portion 202 is formed in a cylindrical shape having a central axis along the first direction D1. The side wall portion 202 extends from the second surface 201b of the top plate 201 to the side opposite to the first surface 201a. A cover member 203 is attached to the end portion 202a of the side wall portion 202 on the side opposite to the top plate 201.

[0057] The cover member 203 is formed, for example, in an annular plate shape having an opening. The cover member 203 is fixed to the end portion 202a of the side wall portion 202 by a cover fixing member such as a screw. The above top plate 201, side wall portion 202, and cover member 203 are formed of, for example, an insulating and light-shielding material, such as black resin, to constitute an insulating and light-shielding housing 200. In addition, the housing 200 holds the electron tube 100 by sandwiching the electron tube 100 between the cover member 203 and the top plate 201 in the first direction D1.

[0058] Refer to Figures 4 to 7 , and the structure of the electron tube 100 will be described. Figure 4 is a perspective view of the electron tube 100. Figure 5 is a top view of the electron tube 100. Figure 6 is a schematic cross-sectional view of the electron tube 100. Figure 7 is a schematic top view of the electron multiplier section.

[0059] The electron tube 100 includes a light incident window 102, a photoelectric conversion section 102s, a side tube 103, a base 104, a base member 105, pins 106, an electron multiplier section 110, and a positioning member 120. The light incident window 102, the side tube 103, and the base 104 constitute a frame 107. The light incident window 102 includes a light incident surface 102a and a back surface 102b on the side opposite to the light incident surface 102a. The light incident window 102 is made of, for example, a light-transmitting material such as glass, and transmits the light L2 incident from the light incident surface 102a to the back surface 102b. The light incident window 102 is formed, for example, in a circular flat plate shape (i.e., a circular plate shape).

[0060] The photoelectric conversion section 102s is provided on the back surface 102b of the light incident window 102 serving as a base material section. That is, the photoelectric conversion section 102s is disposed in the frame 107 so as to face the light incident window 102. The photoelectric conversion section 102s includes a photoelectric conversion layer formed of a thin film of a compound semiconductor such as GaAs, and emits photoelectrons according to the light L2 incident from the light incident window 102. In addition, the photoelectric conversion section 102s may be a so-called alkaline photocathode. The photoelectric conversion section 102s is, for example, a transmissive photocathode.

[0061] The side tube 103 is formed of an insulating material such as ceramics into a tubular shape (a circular tubular shape in this case) with both ends open. One end of the side tube 103 is sealed by the light incident window 102. The base 104 is formed of an insulating material such as ceramics into a plate shape (a circular plate shape in this case), and seals the other end of the side tube 103. Thereby, a vacuum region can be formed inside the side tube 103. In the present embodiment, for example, a voltage can be applied to the photoelectric conversion unit 102s such that the base 104 side becomes the GND potential (such that the photoelectric conversion unit 102s is the negative potential and the base 104 side is the ground potential) (see Figure 2 ).

[0062] The base member 105 is provided on the base 104 so as to be located inside the side tube 103. The base member 105 has a surface facing the photoelectric conversion unit 102s, that is, the top surface 105a, and is formed of an insulating material such as ceramics into a rectangular parallelepiped-shaped block protruding convexly from the base 104 toward the photoelectric conversion unit 102s. A plurality of (for example, the same number as the following channels ch) pins 106 are penetrated through the base member 105 so as to be able to output the electrical signals detected by the electron multiplier 110 to the outside respectively. For example, one end of the pin 106 reaches the surface (top surface 105a) of the base member 105 on the side opposite to the base 104, and the other end of the pin 106 protrudes from the surface of the base member 105 on the base 104 side to the outside of the side tube 103. In addition, the base member 105 may be integrally formed with the base 104, and the pin 106 and the electron multiplier 110 may be electrically connected via other conductive members such as wirings.

[0063] The electron multiplier 110 multiplies the electrons emitted from the photoelectric conversion unit 102s. The electron multiplier 110 is, for example, a semiconductor element. The electron multiplier 110 is disposed inside the housing 107. The electron multiplier 110 is disposed on the top surface 105a of the base member 105 so as to face the photoelectric conversion unit 102s along the first direction D1. More specifically, the electron multiplier 110 includes a back surface 110r and a front surface 110s, and is disposed on the top surface 105a of the base member 105 such that the back surface 110r (that is, the following electron incident surface 111s) faces the photoelectric conversion unit 102s (such that the front surface 110s faces the top surface 105a side of the base member 105).

[0064] As an example, the electron multiplier 110 is electrically connected to the pin 106 by bump bonding. The electron multiplier 110 is, for example, an AD (Avalanche diode). The electron multiplier 110 receives the incidence of photoelectrons from the photoelectric conversion unit 102s, generates multiplication based on electron injection, and generates further multiplication based on avalanche multiplication. In addition, in the present embodiment, the electron multiplier 110 uses a back-illuminated semiconductor element.

[0065] The electron multiplication section 110 has a first section 111 and a second section 112. The first section 111 has a surface facing the photoelectric conversion section 102s, that is, an electron incident surface 111s. The electron incident surface 111s includes a plurality of channels ch arranged separately from each other along a second direction D2 intersecting the first direction D1. In other words, the electron incident surface 111s is a photoelectron detection surface in the electron multiplication section 110, including sensitivity regions as the plurality of channels ch and insensitive regions R formed between the respective channels ch. The electron multiplication section 110 multiplies (detects) photoelectrons in each of the plurality of channels ch. That is, the plurality of channels ch multiply each of the electrons emitted from the photoelectric conversion section 102s according to each of the plurality of lights L2 incident from the photoelectric conversion section 102s. In addition, in the present embodiment, the electron multiplication section 110 is a so-called one-dimensional sensor (line sensor) in which the plurality of channels ch are arranged in a line, but may also be a so-called two-dimensional sensor (area sensor) in which the plurality of channels ch are arranged in multiple lines.

[0066] The second section 112 is provided at least on both end sides of the electron incident surface 111s in the second direction D2. In the present embodiment, the second section 112 is formed in a rectangular frame shape so as to surround the electron incident surface 111s when viewed from the first direction D1. The second section 112 protrudes more toward the photoelectric conversion section 102s than the electron incident surface 111s, and thus is formed thicker than the first section 111. A potential is applied between the photoelectric conversion section 102s and the electron incident surface 111s such that the photoelectrons emitted from the photoelectric conversion section 102s are accelerated toward the electron incident surface 111s with a desired acceleration. In the present embodiment, a voltage is applied in such a manner that the electron incident surface 111s side is set to the GND potential (in such a manner that the photoelectric conversion section 102s is a negative potential and the electron incident surface 111s side is a ground potential).

[0067] The second section 112 has a surface facing the photoelectric conversion section 102s, that is, a surface 112a. The second section 112 has a plurality of first reference lines (marking portions) 113 formed on the surface 112a. The plurality of first reference lines 113 are so-called alignment lines and may also be physical structures such as metal films, grooves, or protrusions that can be visually recognized. The plurality of first reference lines 113 serve as a reference for position alignment of the following positioning member 120.

[0068] A plurality of first reference lines 113 have a pair of first lines 113a and a pair of second lines 113b, which are respectively arranged at the center of the short side direction (third direction D3) of the first part 111 and at the center of the long side direction (second direction D2) of the first part 111. The pair of first lines 113a are straight lines formed on the surface 112a along the second direction D2. The pair of first lines 113a are formed on both sides of the second part 112 in the second direction D2 so as to face each other with the first part 111 interposed therebetween. That is, the pair of first lines 113a are straight lines extending outward from both end portions of the first part 111 in the second direction D2 in the second direction D2.

[0069] The pair of second lines 113b are straight lines formed on the surface 112a along the third direction D3. The pair of second lines 113b are formed on both sides of the second part 112 in the third direction D3 so as to face each other with the first part 111 interposed therebetween. That is, the pair of second lines 113b are straight lines extending outward from both end portions of the first part 111 in the third direction D3 in the third direction D3.

[0070] Figure 8 (a) to (c) of FIG. are views of the electron multiplier unit 110 and the positioning member 120 as viewed from the light incident surface 102a. Figure 8 (a) of FIG. is a view showing only the positioning member 120. Figure 8 (b) of FIG. is a view showing only the electron multiplier unit 110. Figure 8 (c) of FIG. is a view showing a state in which the positioning member 120 is arranged on the electron multiplier unit 110.

[0071] Refer to Figure 6 and Figure 8 The positioning member 120 will be described. The positioning member 120 is formed of a light-transmissive material, such as a light-transmissive resin or glass, and is formed separately from the light incident window 102 as a rectangular member having the second direction D2 as the long side direction, and is fixed (e.g., adhered) to the light incident surface 102a of the light incident window 102. The positioning member 120 is fixed to the light incident surface 102a in such a manner that the light passage portion 123 faces the photoelectric conversion portion 102s and the light L2 that has passed through the light passage portion 123 is incident on a desired region of the photoelectric conversion portion 102s. The positioning member 120 is formed in a plate shape. The positioning member 120 has a first surface 120a on the side of the light incident surface 102a and a second surface 120b on the side opposite to the first surface 120a.

[0072] An antireflection film (antireflection coating) 120s is formed on at least one of the first surface 120a and the second surface 120b of the positioning member 120. In the case of the present embodiment, the antireflection film 120s is formed on both the first surface 120a and the second surface 120b. Therefore, the positioning member 120 is arranged such that the first surface 120a faces the light incident surface 102a and is fixed to the light incident surface 102a via the antireflection film 120s.

[0073] The positioning member 120 has a plate-like portion 121 and a cylindrical lens array (optical element) 122. The plate-like portion 121 is formed in a rectangular shape with the second direction D2 as the long side direction. The plate-like portion 121 includes the second surface 120b. The corner portion 121c of the plate-like portion 121 is chamfered into a C-shaped surface, for example. The plate-like portion 121 has a light passing portion 123, a frame portion 124, a reference portion 125, and a plurality of second reference lines (marking portions) 126.

[0074] Viewed from the first direction D1, the light passing portion 123 is formed at the center of the plate-like portion 121. The light passing portion 123 is formed in a rectangular shape with the second direction D2 as the long side direction. The light passing portion 123 allows the light L2 from the spectroscopic unit 2 to pass through to the light incident surface 102a of the light incident window 102. The positioning member 120 and the light passing portion 123 are arranged so as to overlap the electron multiplication unit 110 when viewed from the first direction D1.

[0075] When viewed from the first direction D1, the frame portion 124 is formed in a rectangular frame shape so as to surround the light passing portion 123. In addition, the frame portion 124 does not necessarily need to have light transmissivity and may be formed of a light-shielding material separate from the light passing portion 123.

[0076] The reference portion 125 is formed on the frame portion 124. The reference portion 125 serves as a reference for mechanical positioning with respect to the spectroscopic unit 2. The reference portion 125 has a first through hole 125a and a second through hole 125b. The first through hole 125a is formed at one end of the frame portion 124 in the second direction D2. The first through hole 125a is a through hole along the first direction D1. The first through hole 125a is formed in a circular shape when viewed from the first direction D1, for example. The first through hole 125a is a mechanical structure and serves as a position reference for the position with respect to the spectroscopic unit 2. That is, the first through hole 125a provides a mechanical position reference by inserting and fitting a protrusion, such as a protrusion having a circular cross-section, into the inner wall surface of the first through hole 125a.

[0077] The second through-hole 125b is formed at the other end of the frame portion 124 in the second direction D2. The second through-hole 125b is a through-hole along the first direction D1. The second through-hole 125b is an oblong hole that is oval with the second direction D2 as the long side direction when viewed from the first direction D1. The second through-hole 125b is a mechanical structure and serves as an angular reference for the angle relative to the spectroscopic unit 2. That is, the second through-hole 125b is at a position different from the first through-hole 125a. By inserting a protrusion with mobility into the inside of the second through-hole 125b, together with the first through-hole 125a, it restricts the rotation of the positioning member 120 and provides an angular reference that enables mechanical angle adjustment.

[0078] As Figure 8 As shown in (a) of [], a plurality of second reference lines 126 are formed on the second surface 120b. The plurality of second reference lines 126 have a pair of first lines 126a and second lines 126b, which are respectively arranged at the center in the short side direction (third direction D3) of the light passing portion 123 and at the center in the long side direction (second direction D2) of the light passing portion 123. The plurality of second reference lines 126 are so-called alignment lines used when positioning the positioning member 120 with respect to the electron multiplying unit 110, and may be physically recognizable structures such as metal films, grooves, or protrusions. In addition, a plurality of first reference lines 113 may also be formed on the light incident window 102, which is the base material portion on which the photoelectric conversion portion 102s is formed. That is, a marking portion (a plurality of first reference lines 113 or a plurality of second reference lines 126) is formed on at least one of the positioning member 120, the light incident window 102 (base material portion) provided with the photoelectric conversion portion 102s, and the electron multiplying unit 110.

[0079] A pair of first lines 126a are straight lines along the second direction D2 formed on the second surface 120b. The pair of first lines 126a are formed on both sides of the frame portion 124 in the second direction D2 so as to face each other across the light passing portion 123. That is, the pair of first lines 126a are straight lines extending outward from both end portions of the light passing portion 123 in the second direction D2 in the second direction D2.

[0080] The second line 126b is a straight line along the third direction D3 formed on the second surface 120b. The second line 126b is formed on one side of the light passing portion 123 in the third direction D3. That is, the second line 126b is a straight line extending outward from one end portion of the light passing portion 123 in the third direction D3 in the third direction D3.

[0081] Here, refer to Figure 8 to describe the positioning sequence of the electron multiplying unit 110 and the positioning member 120. First, as Figure 8 shown in (a) of [], prepare the positioning member 120. Next, as Figure 8As shown in (b) thereof, confirm that the electron multiplier section 110 can be visually recognized. Next, as Figure 8 shown in (c) thereof, the positioning member 120 is fixed to the light incident surface 102a such that the first line 113a of the electron multiplier section 110 coincides with the first line 126a of the positioning member 120 and the second line 113b of the electron multiplier section 110 coincides with the second line 126b of the positioning member 120. Thereby, the positioning member 120 is positioned with respect to the electron multiplier section 110.

[0082] In addition, the positioning member 120 is originally positioned and fixed to the light incident window 102 such that light (light L2 of a plurality of wavelengths in the present embodiment) from an external device is appropriately incident on a desired region of the photoelectric conversion section 102s. However, since the photoelectric conversion section 102s is formed of a thin film, it is difficult to provide a reference line (marking section) on the photoelectric conversion section 102s itself. Therefore, in the case of a transmissive photoelectric conversion section 102s (transmissive photoelectric surface) such as the electron tube 100 in the present embodiment, the positioning member 120 can also be positioned by providing a reference line on the light incident window 102 which is the base material section on which the photoelectric conversion section 102s is formed. However, when providing a reference line on the light incident window 102 which is both the light incident surface and the light exit surface, there is also a possibility that this reference line may become an obstacle during light detection. Therefore, in the present embodiment, a reference line is provided on the electron multiplier section 110. In the case of a transmissive photoelectric surface, the photoelectrons emitted from the photoelectric conversion section 102s substantially have a positional relationship of projection toward the electron multiplier section 110. Therefore, by appropriately positioning the electron multiplier section 110, the positioning of the photoelectric conversion section 102s also becomes appropriate. Further, in the present embodiment, the reference line is provided in the second part 112 of the electron multiplier section 110, that is, in a region other than the electron incident surface 111s, so the reference line does not become an obstacle to electron multiplication. In addition, in the case of an electron tube 100B having a reflective photoelectric surface as shown in Figure 17 , even if a reference line is provided on the base material section on which this photoelectric surface is formed, this reference line does not become an obstacle during light detection, and the positioning member 120 can be appropriately positioned.

[0083] As Figures 6 to 9 shown, the cylindrical lens array 122 is provided on the surface of the light passage section 123 and includes a second surface 120b. The cylindrical lens array 122 receives the incidence of the light L2 from the spectroscopic section 2 and emits the light L2 toward the light incident surface 102a.

[0084] The cylindrical lens array 122 includes a plurality of cylindrical lenses (optical structures) 122a. The plurality of cylindrical lenses 122a are arranged along the second direction D2. The plurality of cylindrical lenses 122a each have a curvature in the plane along the second direction D2. The cylindrical lenses 122a are each arranged so as to protrude toward the side opposite to the light incident surface 102a of the light incident window 102. The plurality of cylindrical lenses 122a are aligned with respective positions of the plurality of channels ch. Specifically, as Figure 9 shown, the positions of the cylindrical lenses 122a are aligned such that the light L2 emitted from the plurality of cylindrical lenses 122a is incident on respective ones of the plurality of channels ch of the corresponding electron multiplying section 110. That is, the plurality of cylindrical lenses 122a are positioned such that the light L2 does not enter the insensitive region R of the electron multiplying section. Thereby, the light can be efficiently incident on the plurality of channels ch respectively.

[0085] In addition, the cylindrical lenses 122a may be arranged at equal intervals or at unequal intervals along the second direction D2. In the case where the cylindrical lenses 122a are arranged at unequal intervals, the arrangement of the cylindrical lenses 122a can be set as follows. That is, when the principal ray of the light L2 is incident on the cylindrical lens 122a at an incident angle θ, the center of the cylindrical lens 122a may be moved only by f·tanθ from the center of the channel ch of the electron multiplying section 110 (f is the focal length). When the light L2 is imaged by a non-telecentric optical system, the principal ray angle in the image plane varies depending on the field of view. Therefore, as a result, it is advantageous to make the cylindrical lenses 122a have unequal intervals. In addition, in this case, the optical system for imaging the light L2 is not limited to an image-side telecentric configuration. Therefore, it is possible to avoid restrictions on the configuration of the optical system such as the fixation of the distance between the diffraction grating 23 and the imaging lens 24 for achieving an image-side telecentric configuration and the enlargement of the lens. Further, in the present embodiment, the cylindrical lens array 122 (cylindrical lenses 122a) is integrally formed with the plate-like portion 121, but they may be separate. In this case, the cylindrical lens array 122 (cylindrical lenses 122a) may be fixed on the light passing portion 123 formed of a light-transmissive member on a flat plate, or the cylindrical lens array 122 (cylindrical lenses 122a) may be fixed in an embedded manner in the light passing portion 123 formed as an opening.

[0086] The electron tube 100 configured as described above has each of a pair of protrusions 214 of the insertion housing 200 inserted into the first through-hole 125a and the second through-hole 125b of the positioning member 120, and is clamped by the top plate 201 and the cover member 203 of the housing 200, thereby being mechanically positioned relative to the housing 200. Then, by inserting each of the positioning pins 12c of the mounting portion 12 of the spectroscopic unit 2 into each of the plurality of through-holes 212 of the housing 200, the housing 200 is mechanically positioned and fixed relative to the spectroscopic unit 2. As a result, the electron tube 100 is mechanically positioned relative to the spectroscopic unit 2. That is, the electron tube 100 is mechanically positioned relative to the spectroscopic unit 2 via the housing 200 using the positioning member 120. At this time, within the electron tube 100, the positioning member 120 is positioned relative to the internal structure of the housing 107, that is, the electron multiplier 110, so that the positioning of the spectroscopic unit 2 and the electron multiplier 110 can also be achieved.

[0087] As described above, the electron tube 100 includes a housing 107 including an optical incident window 102, a photoelectric conversion unit 102s and an electron multiplier 110 disposed inside the housing 107, and a positioning member 120 fixed to the light incident surface 102a of the optical incident window 102. Further, the positioning member 120 has a reference portion 125, and this reference portion 125 serves as a reference for mechanical positioning relative to the spectroscopic unit 2. The positioning member 120 is formed separately from the optical incident window 102 and fixed to the optical incident window 102. Therefore, after the positioning member 120 is completed as the electron tube 100 (after the manufacturing process of the electron tube 100 is completed), that is, after the change in mechanical accuracy caused by the influence related to the manufacturing of the electron tube 100 is determined, the positioning member 120 can be fixed to the optical incident window 102 in a desired state. Therefore, the reference portion 125 of the positioning member 120 is not easily affected by deformation in, for example, a heating process for sealing the housing 107 (optical incident window 102) related to the manufacturing of the electron tube 100. Therefore, when the electron tube 100 is mounted on the spectroscopic unit 2, by using the reference portion 125 of the positioning member 120, high-precision positioning corresponding to the mechanical accuracy of the reference portion 125 can be performed. Therefore, according to this electron tube 100, it is possible to easily and highly accurately position relative to the spectroscopic unit 2.

[0088] The positioning member 120 is fixed to the light incident surface 102a such that the light passing portion 123 faces the photoelectric conversion unit 102 and the light L2 that has passed through the light passing portion 123 is incident on a desired region of the photoelectric conversion unit 102s. Thereby, it is possible to perform high-precision positioning for guiding the light L2 from the spectroscopic unit 2 to an appropriate region of the photoelectric conversion unit 102s.

[0089] A marking portion is formed on at least one of the positioning member 120, the light incident window 102 provided with the photoelectric conversion portion 102s, and the electron multiplier portion 110. Thus, highly accurate positioning can be performed by the marking portion.

[0090] The electron multiplier portion 110 has a plurality of channels ch. In this way, when the electron multiplier portion 110 is a multi-channel one having a plurality of channels ch, it is necessary to make the light split by the spectroscopic portion 2 enter the channels ch corresponding to the respective wavelengths, so higher-accuracy positioning is required. Even in such a case, easy and highly accurate positioning can be performed with respect to the spectroscopic portion 2.

[0091] The reference portion 125 has a first through hole 125a serving as a reference for the position with respect to the spectroscopic portion 2 and a second through hole 125b serving as a reference for the angle with respect to the spectroscopic portion 2. Thus, the position and angle with respect to the spectroscopic portion 2 can be easily and highly accurately determined.

[0092] An antireflection film 120s is formed on at least one of the first surface 120a and the second surface 120b of the positioning member 120. Thus, the reflection of light in the positioning member 120 can be reduced.

[0093] The cylindrical lens array 122 is provided on the surface of the light passing portion 123. The cylindrical lens array 122 receives the incidence of the light L2 from the spectroscopic portion 2 and emits the light L2 to the light incident surface 102a. The plurality of cylindrical lenses 122a of the cylindrical lens array 122 are aligned with the respective positions of the plurality of channels ch. Thus, as described above, the light L2 can be efficiently incident on the plurality of channels ch of the electron multiplier portion respectively.

[0094] The spectroscope 1 includes a spectroscopic portion 2 for splitting the detection light L1 into lights L2 of a plurality of wavelengths and emitting them, and an electron tube 100. Thus, the electron tube 100 can be easily and highly accurately positioned with respect to the spectroscopic portion 2.

[0095] The spectroscope 1 includes a filter 22. The filter 22 is arranged in front of the diffraction grating 23 on the optical path of the detection light L1 and reflects or absorbs the light of a specific wavelength band of the detection light L1. Thus, the light that becomes noise with respect to the detection light L1 can be reflected or absorbed by the filter 22.

[0096] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above-described spectroscope 1 and can be arbitrarily deformed. Next, modification examples will be described.

[0097] The electron multiplication section 110 of the electron tube 100 may also not have a plurality of first reference lines 113. In this case, for example, in the positioning of the positioning member 120 and the electron multiplication section 110, the pattern of the semiconductor elements of the electron multiplication section 110 can be used instead of the first reference lines 113. As an example of the pattern of the semiconductor elements, a pattern of a plurality of channels ch on the electron incident surface 111s (for example, a line formed on the outer edge of each channel) can be cited.

[0098] In addition, the positioning member 120 may also not have a plurality of second reference lines 126. In this case, in the positioning of the positioning member 120 and the electron multiplication section 110, any structure (such as the cylindrical lens array 122) or the reference portion 125 of the positioning member 120 can be used instead of the plurality of second reference lines 126.

[0099] Figure 10 It is a diagram for explaining a positioning method without using the first reference line 113 and the second reference line 126. First, as Figure 10 shown in (a), the electron multiplication section 110 is observed from the light incident surface 102a through a camera. Next, any position of the pattern of the plurality of channels ch formed on the electron incident surface 111s of the electron multiplication section 110 is set as a reference, and this reference is aligned with two orthogonal electron lines A displayed on the camera. Next, as Figure 10 shown in (b), the positioning member 120 is arranged on the light incident surface 102a. Next, at the position where the reference portion 125 (the first through hole 125a and the second through hole 125b) of the positioning member 120 is designed to be arranged, two orthogonal electron lines B different from the electron lines A are displayed on the camera. Then, the positioning member 120 is adjusted and fixed on the light incident surface 102a in such a way that the distance between each of the electron lines A and each of the electron lines B is the ideal distance in design, and the reference portion 125 is aligned with the position of the electron lines B (for example, the intersection point of the electron lines B is located at the center of the first through hole 125a).

[0100] In the above embodiment, the reference portion 125 has the first through hole 125a and the second through hole 125b, but the reference portion 125 is not limited to holes and may include at least one of a protrusion, a notch, and an end face. For example, as Figure 11 shown in (a), the reference portion 125 may also be a notch 125c formed on the outer edge of the frame portion 124. In this case, for example, by inserting the protrusion portion 214 formed on the top plate 201 of the housing 200 into the notch 125c (by making the protrusion portion 214 touch the inner surface of the notch 125c), the electron tube 100 can be mechanically positioned relative to the spectroscopic unit 2.

[0101] In addition, as Figure 11As shown in FIG. (b), the reference portion 125 may also be the end face 125d facing the outside of the frame portion 124. In this case, for example, by bringing the protrusion 220 (e.g., a pin) formed on the top plate 201 into contact with the end face 125d, the electron tube 100 can be mechanically positioned relative to the spectroscopic unit 2. Further, as Figure 12 shown in FIGS. (a) and (b), the reference portion 125 may also include a protrusion 125e. In this case, for example, by forming a hole portion in the top plate 201 and inserting the protrusion 125e into the hole portion, the electron tube 100 can be mechanically positioned relative to the spectroscopic unit 2. In either case, the electron tube 100 can be positioned with high precision. In addition, in Figure 11 and Figure 12 , the cylindrical lens array 122 and the light passing portion 123 are omitted.

[0102] In addition, as Figure 13 shown, an opening 123b may be formed in the light passing portion 123 to expose the light incident surface 102a of the light incident window 102 to the outside. That is, in the region where the light L2 passes through the light passing portion 123, the light transmissive material constituting the light passing portion 123 may be removed to form an opening 123b as a gap in the light passing portion 123. In this case, the light L2 from the spectroscopic unit 2 can be incident on the light incident surface 102a without reflection and refraction in the positioning member 120.

[0103] As Figure 14 shown, the positioning member 120 may further include a lens (condensing element) 127. In the illustrated example, the lens 127 is provided, for example, on the second surface 120b of the cylindrical lens array 122. Here, the lens 127 is, for example, a cylindrical lens having a curvature (having a condensing structure) in a plane intersecting the arrangement direction of the channels ch, that is, the second direction D2 (i.e., in a plane intersecting the plane having the curvature of the cylindrical lens 122a). In other words, the lens 127 is a condensing lens having a refractive power in a plane intersecting the arrangement direction of the channels ch, that is, the second direction D2. The lens 127 is arranged so as to protrude toward the side opposite to the light incident surface 102a of the light incident window 102 (protruding on the light incident side of the lens 127). In this case, the field of view on the plane intersecting the arrangement direction of the channels can be expanded. In addition, the lens 127 may be arranged so as to protrude toward the light incident surface 102a side of the light incident window 102 (protruding on the light exit side of the lens 127), or may have a shape protruding toward both the side opposite to the light incident surface 102a of the light incident window 102 and the light incident surface 102a side of the light incident window 102 (protruding on both the light incident side and the light exit side of the lens 127).

[0104] In addition, as Figure 15As shown, the optical splitter 1 may also have a housing 200A instead of the housing 200. The housing 200A does not have the protrusion 214 and is different from the housing 200 of the above-described embodiment in this regard. When using such a housing 200A, the electron tube 100 can be easily and highly accurately positioned relative to the optical splitting unit 2 by using the assembly jig 300. Hereinafter, the positioning using the assembly jig 300 will be described.

[0105] The assembly jig 300 is formed in a plate shape having a first surface 300a and a second surface 300b on the opposite side of the first surface 300a. The assembly jig 300 is arranged such that the first surface 300a faces (in this case, contacts) the first surface 201a of the top plate 201.

[0106] In this state, the pin 301 passing through the assembly jig 300 is inserted into the through hole 212 of the top plate 201, and the other pin 302 passing through the assembly jig 300 is inserted through the top plate 201 into each of the first through hole 125a and the second through hole 125b of the positioning member 120, so that the electron tube 100, the housing 200A, and the assembly jig 300 are mechanically positioned with respect to each other. In addition, regarding the fixing and positioning to the optical splitting unit 2, it is the same as the housing 200 of the above-described embodiment. Therefore, by using this assembly jig 300, the electron tube 100 can be easily and highly accurately positioned relative to the optical splitting unit 2.

[0107] Here, in the above-described embodiment, the electron tube 100 having an electron multiplication unit 110 composed of semiconductor elements such as HPD is exemplified. However, the electron tube may also be a photomultiplier tube. Figure 16 FIG. (a) is a schematic diagram showing an electron tube 100A as a photomultiplier tube. Figure 16 The electron tube 100A shown in FIG. (a) is a multi-channel photomultiplier tube (multi-channel PMT). The electron tube 100A has an electron multiplication unit 110A, and the electron multiplication unit 110A in the present embodiment has a focusing electrode 131, a plurality of dynodes 132, and a plurality of anode electrodes 133.

[0108] The focusing electrode 131 focuses the photoelectrons emitted from the photoelectric conversion unit 102s onto the dynode 132. The focusing electrode 131 is arranged to face the photoelectric conversion unit 102s.

[0109] A plurality of dynodes 132 are disposed between the focusing electrode 131 and the plurality of anode electrodes 133. The plurality of dynodes 132 emit secondary electrons according to the incidence of the photoelectrons focused by the focusing electrode 131, and multiply the secondary electrons. The plurality of dynodes 132 are arranged in multiple stages between the focusing electrode 131 and the plurality of anode electrodes 133 to form a channel ch. That is, the electron multiplier section 110A is formed by arranging a plurality of channels ch arranged in multiple stages by the plurality of dynodes in the second direction D2. In this case, the electron multiplier section 110A has a plurality of channels ch arranged in one direction, and is used to multiply each of the electrons emitted from the photoelectric conversion section 102s according to each of the plurality of lights L2 incident from the light incident window 102.

[0110] As Figure 16 shown in (b) of Figure 16 and (c) of

[0111] In this case, as in the above-described embodiment, the positioning member 120 can also be configured. A plurality of first reference lines 134 (marking portions) serving as the reference for the alignment of the position of the positioning member 120 are drawn on the electron multiplier section 110A (specifically, the focusing electrode 131 in the present embodiment). The second reference line 126 of the positioning member 120 is aligned with the first reference line 134. Therefore, even for the electron tube 100A which is a photomultiplier tube, the positioning can be easily and highly accurately performed in the same manner as the electron tube 100. Specifically, by mounting the reference portion 125 of the positioning member 120 as a mechanical reference on the spectroscopic section 2, the spectroscopic section 2 and the electron tube 100A (further, the internal structure such as the electron multiplier section 110A, etc.) can be highly accurately positioned. Figure 17 In addition, as

[0112] shown, the electron tube may also be an electron tube 100B which is a side-incident type photomultiplier tube. The electron tube 100B is a photomultiplier tube having a reflective photocathode. The electron tube 100B has a tube 401, a grid 402, a photoelectric conversion section 403, a plurality of dynodes 406 (electron multiplier section 110B), and an anode 405.

[0113] The photoelectric conversion unit 403 is a reflective photoelectric surface, for example, formed by forming a photoelectric surface on a substrate portion made of metal. The photoelectric conversion unit 403 emits photoelectrons e according to the light L2 incident through the side surface 401a of the tube 401. The electrons emitted from the photoelectric conversion unit 403 are amplified by a plurality of dynodes 406.

[0114] The plurality of dynodes 406 emit secondary electrons according to the incidence of the photoelectrons e from the photoelectric conversion unit 403, and multiply the secondary electrons. The electron multiplier unit 110B is composed of, for example, a plurality of (eight in this example) dynodes 406. Each dynode 406 is formed in a curved shape or a flat plate shape, and emits secondary electrons to the next-stage dynode 406 by the collision of the secondary electrons emitted from the previous-stage dynode 406. Thus, the secondary electrons are successively multiplied. The multiplied secondary electrons are captured by the anode 405.

[0115] As Figure 17 and Figure 18 shown, in this case, the positioning member 120 can also be configured in the same manner as the above-described embodiment. However, in this case, the first surface 120a of the positioning member 120 is formed to be curved in a manner imitating the side surface 401a of the tube 401. Thus, the first surface 120a of the positioning member 120 can be brought into contact with the side surface 401a of the tube 401 that functions as a light incident window, and the positioning member 120 can be fixed to the tube 401. Thus, in the electron tube 100B, positioning can also be easily and highly accurately performed in the same manner as in the electron tube 100. Specifically, by mounting the reference portion 125 of the positioning member 120 as a mechanical reference on the spectroscopic unit 2, the spectroscopic unit 2 and the electron tube 100B can be highly accurately positioned (further, the internal structure such as the electron multiplier unit 110B, for example, in this embodiment, align the reference line provided on the substrate portion of the photoelectric conversion unit 403 with the reference line provided on the positioning member 120).

[0116] As described above, the electron multiplier unit 110B may not have a plurality of channels ch. In this case, especially when the effective area is small, high-precision positioning is required, so this structure is effective.

[0117] In addition, the positioning member 120 may not have a lens, and the reference portion 125 may not be a plurality of mechanical structures such as the first through-hole 125a and the second through-hole 125b, but may have a single mechanical structure. Additionally, the optical system 20 of the beam splitting unit 2 may not have the filter 22, and even when the filter 22 is provided, it may be provided at a stage prior to the diffraction grating 23. For example, it may be disposed at a stage even prior to the collimating lens 21. The antireflection film 120s may not be formed on either the first surface 120a or the second surface 120b of the positioning member 120. Further, the material of the positioning member 120 may be a material having a refractive index close to that of the light incident window 102. Even in this case, the reflection of light in the positioning member 120 can be reduced. Additionally, the cylindrical lens array (optical element) 122 is an optical element having a refractive power, and as long as it receives the incidence of the light L2 from the beam splitting unit 2 and emits the light L2 to the light incident surface 102a, it may be a single non-arrayed lens, a Fresnel lens, a gradient index lens, a diffractive lens, or a condenser prism.

Claims

1. An electron tube, wherein: It is an electron tube installed in an external device. have: a frame having a light incident window including a light incident surface and allowing light from the external device to be incident through the light incident surface; a photoelectric conversion unit disposed in the frame so as to face the light incident window and emitting electrons in response to the light incident from the light incident window; an electron multiplying section, which is disposed in the frame and multiplies the electrons emitted from the photoelectric conversion section; as well as a positioning member, which is formed separately from the light incident window and fixed to the light incident surface, and has a light passing portion for allowing the light from the external device to pass toward the light incident surface, The positioning member has a reference portion serving as a reference for mechanical positioning relative to the external device.

2. The electron tube according to claim 1, wherein: The positioning member is fixed to the light incident surface so that the light passing portion faces the photoelectric conversion portion and the light having passed through the light passing portion enters a desired region of the photoelectric conversion portion.

3. The electron tube according to claim 1 or 2, wherein: A marking portion is formed on at least one of the positioning member, the base portion on which the photoelectric conversion portion is provided, and the electron multiplying portion.

4. The electron tube according to any one of claims 1 to 3, wherein The electron multiplying section has a plurality of channels arranged in at least one direction and configured to multiply each of the electrons emitted from the photoelectric conversion section in response to each of the plurality of lights incident from the light incident window.

5. The electron tube according to any one of claims 1 to 4, wherein The positioning member includes an optical element, which is provided in the light passing portion, receives the incident light from the external device, and emits the light toward the light incident surface.

6. The electron tube according to any one of claims 1 to 5, wherein The reference portion has a position reference as a reference for a position relative to the external device and an angle reference as a reference for an angle relative to the external device.

7. The electron tube according to any one of claims 1 to 6, wherein The reference portion includes at least one of a protrusion, a hole, a cutout, and an end surface formed on the positioning member.

8. The electron tube according to any one of claims 1 to 7, wherein The positioning member has a first surface on the light incident surface side and a second surface on the opposite side to the first surface. An antireflection film is formed on at least one of the first surface and the second surface.

9. The electron tube according to any one of claims 1 to 4, wherein The light passing portion has an opening formed therein for exposing the light incident surface to the outside.

10. The electron tube according to claim 4, wherein The positioning member includes an optical element, which is disposed in the light passing portion, receives the incident light from the external device, and emits the light toward the light incident surface. The optical element includes a plurality of optical structures aligned with respective locations of the plurality of channels.

11. The electron tube according to claim 10, wherein: The optical element includes a light-concentrating element provided on a surface of the optical element opposite to the light incident surface and having a light-concentrating structure in a surface intersecting with the arrangement direction of the channels.

12. A spectrometer, wherein: have: a spectroscopic unit as the external device for splitting the detection light into lights of a plurality of wavelengths and emitting the lights; and The electron tube according to any one of claims 1 to 11.

13. The optical splitter according to claim 12, wherein: The spectroscopic unit comprises: a dispersing element, disposed on an optical path of the detection light, for splitting the detection light into the multiple wavelengths of light; as well as The wavelength selection element is arranged in the optical path of the detection light at a stage before the dispersion element, and reflects or absorbs light of a specific wavelength band of the detection light.

Images